Messages in this thread | | | Date | Thu, 16 Apr 2009 09:23:09 +0800 | From | Miao Xie <> | Subject | Re: [PATCH] sched: fix off-by-one bug in balance_tasks() |
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on 2009-4-15 19:41 Peter Zijlstra wrote: > On Wed, 2009-04-15 at 10:49 +0800, Miao Xie wrote: >> If the load that need be moved equals the half weight of a task, I think >> it is unnecessary to move this task. Or this task will be moved back and >> forth. > > That's actually desirable. Consider the 3 tasks on 2 cpus statically > infeasible scenario. There you'd want the tasks to bounce around a bit > in order to provide fairness.
I see. Thanks for your explanation.
Miao Xie > >> Signed-off-by: Miao Xie <miaox@cn.fujitsu.com> >> --- >> kernel/sched.c | 2 +- >> 1 files changed, 1 insertions(+), 1 deletions(-) >> >> diff --git a/kernel/sched.c b/kernel/sched.c >> index 5724508..44926c8 100644 >> --- a/kernel/sched.c >> +++ b/kernel/sched.c >> @@ -3085,7 +3085,7 @@ next: >> if (!p || loops++ > sysctl_sched_nr_migrate) >> goto out; >> >> - if ((p->se.load.weight >> 1) > rem_load_move || >> + if ((p->se.load.weight >> 1) >= rem_load_move || >> !can_migrate_task(p, busiest, this_cpu, sd, idle, &pinned)) { >> p = iterator->next(iterator->arg); >> goto next; > > > >
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